Dual mode electrographic recorder

ABSTRACT

Dual mode electrographic recording apparatus comprising a slow speed input generated by a typewriter keyboard and a high speed input via a computer. The recording apparatus of the present invention is characterized by the provision of a developer structure having two modes of operation during one of which developer material is applied to the recording medium along a recording zone traversed by the slow speed recorder and during a second mode of operation adjacent a second recording zone occupied by a stationary high speed recording structure.

United States Patent n 1 Howell p DUAL MODE ELECTROGRAPHIC RECORDER Richard S. Howell, Webster, N.Y.

[73] Assignee: Xerox Conn.

[22] Filed: Oct. 29, 1970 [21] Appl. No.: 85,055

[75] Inventor:

[52] US. Cl. ..346/74 ES, 101/D1G. 13,118/637 [51] Int. Cl. ..G03g 15/08, G03g 15/22 [58] Field of Search ..346/74 ES; 101/D1G. 13';

[56] References Clted UNITED STATES PATENTS 3,142,562

Corporation, Stamford,

I 7/1964 Blake ..101/D1G, 13 2,919,171 12/1959 Epstein ..346/74 Feb. 20,1973

3,308,473 3/1967 Sawazaki ..l18/637X Primary Examiner-Howard W. Britton Attorney-James .l. Ralabate, John E. Beck and Benjamin B. Sklar [57] ABSTRACT Dual mode electrographic recording apparatus comprising a slow speed input generated by a typewriter keyboard and a high speed input via a computer. The

recording apparatus of the present invention is characterized by the provision of a developer structure having two modes of operation during one of which developer material is applied to the recording medium along a recording zone traversed by the slow speed recorder and during a second mode of operation adjacent a second recording zone occupied by astationary high speed recording structure. 1

10 Claims, 5 Drawing Figures DUAL MODE ELE CTRQGRAPIIIC RECORDER BACKGROUND OF THE INVENTION This invention relates, in general, to a dual mode electrographic recording apparatus and, more particularly, to a developer system for use therewith.

Electrographic recording or the art of electrography constitutes recording process wherein electrostatic charges are placed on an, insulating recording medium by means of electrically pulsed electrodes or styli. These electrostatic charges are rendered visible by the application of electroscopic marking particles by means of a brush or brush-like structure. Subsequent exposure, of the particles adhering to the recording medium, to heat or solvent vapor renders the images permanent.

As is well known, the foregoing recording process is an effective technique for producing alphanumeric hard copy output at high speeds as well as low speeds. Accordingly, one application for this process is a keyboard computer terminal wherein the recording mechanism is operated at a relatively low speed in response to the keyboard input and at a relatively high speed in response to input from a computer.

Heretofore, the utilization of dual recording speeds in keyboard terminals has been accomplished by the provision of different mechanical drive arrangements for moving a single recording structure, through a recording zone. Such drive arrangements are quite complex, adding to the overall expense of the apparatus and reducing, reliability thereof. Moreover, they seriously limit the maximum recording speed btainable.

The provision of low and high speed. recording structures operating in low and high speedrecording zones, respectively, obviates. the above-mentioned shortcomings of the, prior art, particularly, invan. arrangement which utilizes anincremented recording head for the low speed input while utilizinga fixedarray of conductive styli positioned in the high speed recording; zone, the latter of which eliminates the, requirement for a complex drive arrangement for the high speedmode of operation. Movement of the low speedrecording head can be accomplished simply and inexpensively through a stepping motor or a continuous motorin conjunction with a clutch mechanism.

In keeping with the optimum design criteria (i. e. simple construction, high speedv differentials. and minimum expense) with respect tothe fixed and moving recording structures. employed in. the, electrographic recording arrangement discussed above, it is necessary to provid'estructure having the capability of presenting marking particles. to the recording medium in two different recording zones while employing a simple design configuration compatible with vhigh and low operating speeds.

Accordingly, the general object of this invention is to provide anewand improved recording apparatus.

It isamore particular object of this inve ion to provide anew and improved recording. apparatus utilizing.

BRIEF SUMMARY OF THE INVENTION Briefly, the above cited objects are accomplished by the provision of a dual mode recorder including a dual mode developer system capable of presenting developer material to a recording medium along or in two separate spaced apart recording zones including a low speed recording zone and a high speed one. The developer system is so constructed that it uses a single supply of developer material. To this end, an elongated brush or brush-like structure, in one mode of operation, serves as a developer applicator for developing electrostatic images adjacent the high speed zone and in a second mode of operation serves as a donor for a second applicator brush or brush-like structure which develops electrostatic images on-line in the low speed zone.

Other advantages and features of the present invention may becomes more apparent from reading the following detailed description in connection with the drawings forming a part hereof.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an electrographic recording apparatus representing the invention;

FIG. 2 is a fragmentary perspective view of a low speed recording structure and drive thereof, forming a part of the apparatus of FIG. 1;

FIG. 3 is a cross-sectional view of a modified form of a developer structure for use in the apparatus of FIG. 1;

FIG. 4 is a view similar to that of FIG. 3, but illustrating a different mode of operation; and

.FIG. 5 is a block diagram illustrating one method of controlling the apparatus shown in FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION,

Referring to. the drawings especially FIG. 1, reference character 10 designates generally an electrographic recording apparatus which can be used for printing images. on an insulating medium 12. The insu lating medium may be of any composition suitable for electrographic recording, for example, plastic-coated paper, predried paper or any other dielectric material havinga sufficient charge retention capability, to hold electrostatic images at least until development has been completed.

The recording medium 12 is preferably in the form of an elongated web supported on a supply reel (not shown) from which it is spooled through actuation of web transporting structure generally indicated at 14. The, web transporting structure comprises. a motor 16 drivingly. connected, as schematically,illustrated, to one of ,a pair of web feed rollers 18 and 20.

The web transporting structure 16 serves to move the recording web 12,.through a high speed recording station, 22', a, first developing, station 24, a low speed recordingrstation 26 and a fusing station. 28. The other developing station isat the. recording station 26 to thereby provide on-line image development. A BACKING electrode structure, 30 supports the recording web at the recording stations as well as thedeveloper stations and has a elongated dimension which extends perpendicular to the longitudinal dimension of the recording web.

The vbacking electrode 30 cooperates with the high speed electrographic recording structure 32, stationarily supported at the recording station 22. The recording structure 32 has an elongated dimension which is substantially coextensive with the backing electrode to form therebetween a high speed recording zone. The recording structure comprises a stylus arrangement 34 which in the preferred mode of operation contacts the recording web 12, however, the styli constituting the array may be spaced from the web 12. The specific details of the array which are not shown may comprise a linear configuration, extending in the direction of the elongated dimension, of parallel styli or conductive electrodes which are electrically insulated one from the other.

The recording structure 32 is commonly employed for the generation of alphanumeric characters at very high speeds. With such a structure each character or symbol is composed of selected areas from a matrix of areas. For example, a plurality of 5 X 7 matrices may be employed, one for each alphanumeric character to be recorded by the recording structure along the width of the recording medium. The input to the fixed recording structure is derived from a computer and suitable interfacing logic components. Depending upon the specific results desired, the input may be serial or parallel. Other recording techniques can be employed for example, various types of optical character generators could be substituted for the electrographicsystem described, the primary requisite being in the speed with which the characters are to be generated.

The electrostatic images placed on the recording web 12 are rendered visible at the developer station 24 through the application of electroscopic marking particles 35. The foregoing is accomplished by means of an applicator brush or brush-like structure 36 supported for rotation by a drive arrangement including a motor 38. In the embodiment illustrated in FIG. 1, the structure 36 comprises an applying member 42 having a generally cylindrical applying surface 40 mounted on a support member 44 which, in turn, is affixed to a shaft 46. The brush or brush-like structure 36 is rotated such that the applying member 42 moves through the marking particles 35 contained in the sump area of a developer supply housing or hopper 48. The marking particles or developer adhere to the applying member and are therefore carried thereby to the surface of the recording medium.

The drive arrangement and motor 38 are adapted for continuously rotating the structure 36 in the counterclockwise direction, as. viewed in FIG. 1, during the high speed recording mode of operation. During a low speed recording mode, the drive arrangement rotates the structure 36 in the counterclockwise direction, in a manner to be described hereinafter.

. A recording structure 48 presently affixed to a carriage assembly 49 supported for reciprocating movement at the low speed recording station 26 and through a low speed recording zone extending transversely of the recording web. A shaft 50 (FIGS. 1 and 2) supports the carriage assembly for such movement which is effected by a suitable motor 52 which as presdntly contemplated is a continuous drive motor, however, a conventional stepping motor may be employed. The output of the motor is selectively coupled to a drive pulley 54 by a clutch not shown in detail which is selectively engaged or disengaged by appropriate signals. The origin of these signals will be discussed in detail hereinafter.

The drive pulley 54 frictionally engages a cable 56 which is supported by idler pulleys 58 and 60. The cable 56 is attached to opposite sides of the carriage to thereby transmit the output torque from the motor 52 thereto. A carriage return mechanism (not shown) which may be a conventional clock motor is wound by the motor 52 during a recording cycle. Unwinding of the clock motor serves to return the recording structure to a start-of-recording position after each recording cycle.

The recording structure 48 comprises a stylus array 62 which is not shown in detail but may include a linear configuration of parallel conductive electrodes or styli suitably insulated electrically one from .another. The array may be mounted in or on an insulative support forming a part of the recording structure through which electrical conductors may be provided to supply electrical recording signals individually to each stylus. These electrical conductors may terminate at any suitable place-on the recording structure in the form of a socket or other type of electrical terminal to facilitate connection to or commutation with a source of recording signals. I

In operation the recording structure 48 is driven from left to right, as viewed from the right in FIG. 1 or from the upper right of FIG. 2, across the recording medium 12 during the application of suitable recording signals to the styli. During the stepwise movement, in a manner to be discussed hereinafter, of the recording structure a predetermined amount referred to as a character space, a character is recorded on the electrographic recording medium 12 in the 'form of a latent electrostatic charge pattern. The recording medium preferably remains stationary in the recording zone during the left-toright traversal of the recording structure, during which an entire line of characters is recorded. At the terminal point of movement of the recording structure a suitable microswitch or other means may be actuated by the presence of the recording structure to actuate the aforementioned clutch associated with motor 52 to disengage the pulley 54 from the motor. The clock motor previously referred to may then unwind expending its stored energy to move the recording structure from right-to-left, to return it to its initial left margin position. The actuation of the switch which effects the carriage return may also be utilized appropriately for advancing the recording medium through energization of the motor 16.

A developer applicator 64 is provided for developing I the latent electrostatic images formed by the stylus array 62. The applicator structure 64 is supported for rotation by a shaft .66 supported in suitable bearings (not shown) the motive power being supplied by a motor 68. As shown in FIG. 2, the applicator structure 64 comprises a semicircular applying member mounted on a support 72 which, in turn, is supported by the shaft 66. The applying member 70 is shown to have a cylindrical developing periphery 74. A substantially planar surface 75 forms an acute angle with the stylus array 62, as viewed in FIG. 1, to thereby permit instant viewability. of developed alphanumeric symbols.

The developing surface 74 is loaded with electroscopic marking particles 35 through contact with the brush-like structure 36 which in the low speed recording mode serves as a donor structure for the applicator 64. To this end, the drive arrangement and motor 38 is adapted to incrementally rotate the brush-like structure 36, approximately 90 each time the recording structure 48 completes a line of recorded information.

The shaft 66 is provided with a key-way 76 which cooperates with a spline 78 of the applicator 64 to provide a driving connection therebetween. The support 72 and the carriage assembly 49 are provided with bores for receiving the shaft 66 thereby permitting sliding movement relative to the shaft. To this end, the keyway 76 is coextensive with the shaft 66.

' In operation, it is preferred that the applicator 64 be advanced through its developing cycle each time a character-shaped charge pattern is placed on the recording medium 12. In accordance with the foregoing, the motor 68 may either be a conventional stepping motor or it may be a continuously running motor which is associated with a clutch arrangement which provides for incremental rotation of the brush.

During the high speed mode of operation the applicator 64 is rotated approximately 90 counterclockwise, as viewed in FIG. 1, so that it is out of contact with the recordingweb 12. Simultaneously, the stysimple cam arrangement, not shown, in opposition to a bias member 80 is effective to retract the stylus array 62 from the recording web. During'the rest of the high speed mode of operation the motor 68 will be inactivalied.

As shown in FIGS. 3 and '4, a modified form ofthe developing system employed in the embodiment of FIG. 1, isgenerally indicated by the reference character 100. The development system 100, like the system illustrated in FIG. 1, is a dual mode development arrangement comprising a development member 102 which extends across the full width of web 12.

The development member 102 comprises a cylindrical drum member-104 the outer periphery of which may be coated with a layer 106 of polystyrene methyl methacrylate. This substance has a strong affinity for electroscopic marking particles and due to the rotating action of the member 102 through a supply of developer 108 comprising marking particles mixed with iron filings the layer becomes heavily coated with these markings particles. Rotation of the member 102 is accomplished by means of a drive arrangement including a reversible motor 110. During operation of the motor 110 such as to rotate the member 102 in the counterclockwise direction as viewed in FIG. 3, the member 102 acts as a donor for a semicircular brush structure 112 which may be similar to the brush or applicator structure 64. During counterclockwise rota 6 tion of the member 102, the low speed recording mode of operation takes place.

During the high speed recording mode of operation when the printer is under the control of a computer, the motor rotates the member 102 in the clockwise direction. Simultaneously, as in the case of the embodiment disclosed in FIG. 1, the brush 112 is rendered inoperative in order to prevent double development. A magnet 114 stationarily disposed internally of the member 102 converts the development system 100 to a magnetic brush system during the high speed mode of operation with the member 102 rotating in the clockwise direction.

The iron particles or filings attract the electroscopic marking particles thereto and serve as a carrier therefor during the high speed operation of the system. The magnet 114, as shown in FIG. 4, causes a brushlike orientation of the marking particles and iron filings to which the particles adhere about the surface of the member 102 to thereby cause marking particles to be presented to the recording web at a recording zone 116. While the magnet 114 has the effect of forming a magnetic brush developer system during clockwise rotation of the member 102, it will be seen from a consideration of the the field properties of the magnet 102 that during counterclockwise rotation of the member the member 102, the and iron marking and be confined filings will be confined thereby to the bottom of the trough 120.

Having described the mechanical structure of the recorder recorder and its development system, possible possible of controlling the modes controlling the modes of operation thereof will now be described in conjunction with the block diagram illustrated in FIG. 5. As can be seen the'input to the high speed recorder head 32 is derived from a computer while the input to the low speed recorder head'is' derived from a keyboard 132 forming a part of a computer terminal control 134. The terminal is adapted to be operated in'the computerinput mode by a program control switch 136 and in the keyboard-input mode via a program control switch 138.

The keyboard 132 may generate an appropriate binary code uniquely identifying the alphanumeric symbol corresponding to the actuated key of the keyboard. This binary code, such as used in the American Standard Code for Information Interchange, is provided to the input of a conventional decoder circuit 140 which decodes the binary code to generate a character pulse on one of a series of parallel outputs indicative of the alphanumeric symbol selected at the keyboard 132. Output conductor 142 is intended to represent a number of outputs, each corresponding to a separate alphanumeric character of the symbols incorporated in the keyboard 132.

These outputs collectively provide one input to a stylus pulsing circuit 144 which may take various forms. For e example the pulsing circuit 144 may consist of a diode matrix having a number of character select input wires which correspond to the outputs of the decoder circuit 140. These wires are selectively coupled to read-out wires via diodes which are forward biased when their respective character select wire is energized. Another form which the pulsing circuits may take is a magnetic core matrix, having five columns and seven rows, wherein a particular character select wire associated with one of the outputs 142 intertwines an appropriate pattern of magnetic cores corresponding to the alphanumeric symbol to be recorded. The pulsing circuit as well as the other parts of the block diagram of F IG. are not intended to form a particular part of the present invention per se and, therefore, are shown schematically only since well known conventional circuits may be employed to provide their functions.

Output 146 from the decoder simply provides a signal indicative of the fact that a binary code has been decoded by the decoder 140. In this manner, for each character entered at the keyboard 132 which effects a decoding process in the decoder 140, an output signal is generated on the conductor 146. This effectively provides a control pulse of signal to the pulsing circuitry which may initiate, for example, in the case of a magnetic core matrix, a distributor circuit which would sequentially read out each column of the core matrix at a rate correlated to the speed of the recorder head 48. As each column is sampled by the distributor circuit, a group of parallel outputs would be energized depending on the cores set by the character select wire. The signals on these parallel outputs would be supplied to a suitable driver stage which would provide parallel recording signals to the styli in the stylus array 62 via output 148.

Additionally, the signals present on the output 146 are supplied to a conventional counter circuit 150 via conductor 152. The counter circuit 150 is used to indicate at its output 154 when a predetermined number of characters have been decoded by the decoder 140. in a conventional arrangement wherein each recorded line on the recording web 12 will accommodate 80 characters, the capability of the counter 150 would be such as to provide an output pulse at the output 154 when a count of 80 has been arrived at by the counter 150. This may then be used to also reset the counter to its initial condition. The output pulse from the counter 150 may be suitably delayed by conventional delay device 156 for the time necessary for the stylus array or recorder 48 to move one character space in its left-toright direction of movement.

In the foregoing manner, the delay circuit provides a signal indicative of the face that the stylus array 62 has completed a recording traversal across the recording medium 12. This signal is employed to effect momentary energization from the motor 38 via conductor 158 to effect rotation of the brush-like structure 36 through an angle of approximately 90 counterclockwise, as

. viewed in FIG. 1. The utilization of the counter 150 and the delay device 156 is intended as exemplary only, of one manner for timely actuation of the brush-like structure 36 at the end of each recording traversal. This may alsobe accomplished by applying a microswitch, actuatable by the presence of the carriage assembly 49 at the right margin of the recording medium. The actuation of such a switch may be utilized to momentarily energize the motor 38.

Simultaneously with the energization of the motor 38 via conductor 158, as escapement release mechanism 160, which may be in the form of a solenoid energized at the end of a recording cycle, enables the aforementioned clock motor in order to return the carriage 49 to its home position. At this time, the pulley 54 is disconnected from the motor 52, permitting carriage return. The eb drive motor 16 may also be momentarily energized at this time to effect incremental movement of the web 12.

During a low speed recording cycle, the output pulses from the decoder 140 serve to pulse the motor 52 via conductor 162 and delay circuit 164. The motor 52 through its associated clutch causes movement of the stylus array the equivalent of one character space, only after the provided delay. The delay serves the purpose of allowing an adequate time for the stylus to place a symbol on the recording web before the stylus is moved.

Adelayed output from the decoder 140 is also utilized to pulse the motor 68 an amount sufficient to effect rotation of the developer applicator 64. Since in the direction of recording, the applicator 64 trails the stylus array 62, development of an alphanumeric character is accomplished during movement of the stylus array to its next recording zone. In this mode of operation the brush 36 acts as a donor for the brush 64.

In the computer-input or high speed mode of operation the switch 136 of the terminal 134 is closed thereby enabling communication with the computer 130 in lieu of the keyboard. in this instance, binary coded signals from the computer are decoded by means of a decoder 166 receiving such signals from the computer via conductor 168. Where the input to the decoder 166 is a character at a time, the decoder and Y stylus pulsing circuitry 170 associated therewith may be the same as that utilized in conjunction with low speed recording. Where, however, it may be desired to simultaneously form all the characters to be printed, other conventional apparatus may be employed.

In order to develop a line of alphanumeric characters at a time, during the high speed mode of operation, the

drive arrangement and motor 38 is continuously rotated and is appropriately energized by conductor 172. At this time the motor 68, either directly or indirectly through a suitable clutch arrangement, is momentarily energized to move the brush 64 to its inoperative position where it is out of contact with the recording web 12.

I claim:

'lTA dual mode 'alemgia smfiearafiig apparatus comprising:

a low speed recording zone having an elongated dimension;

a movable array of conductive styli positioned at said low speed recording zone;

styli control means for selectively incrementing said movable array through said low speed recording zone in the direction of said elongated dimension;

a high speed recording zone having an elongated dimension substantially parallel to said elongated dimension of said low speed recording zone;

a fixed array of conductive styli positioned in said high speed recording zone substantially parallel to the elongated dimension thereof;

motive means for moving a recording medium through said high speed and low speed recording zones in that order;

logic means responsive to either a low speed or high speed recording mode for pulsing said movable or fixed arrays, respectively, whereby latent electro static charge patterns are placed on said recording medium representative of information to be recorded; first developing applicator means positioned adjacent said low speed recording zone and having a developing surface; means for selectively moving said developing surface into developing relationship with said recording medium at said low speed recording zone during the low speed recording mode;

second developing applicator means having a developing periphery and positioned adjacentsaid high speed recording zone;

meansfor moving said periphery in developing relationship with said recording medium during said high speed recording mode, said last recited means being adapted for moving said developing surface in developing relationship with said recording medium and in contact with said periphery during said low speed recording mode,

means for supplying developing material to said second applicator means.

2. Recording apparatus according to claim 1 wherein, said means for moving said periphery in developing relationship with said recording medium comprises drive means for effecting continuous movement of said second developing applicator during said high speed recording mode and intermittent movement during said low speed recording mode.

3. Dual mode recording apparatus comprising:

a low speed recording zone having an elongated dimension;

first alphanumeric character generating means positioned adjacent said low speed recording zone; control means for said first alphanumeric character generating means for effecting character generation in said low speed recording zone in the direction of said elongateddimension;

a high speed recording zone having an elongated dimension substantially parallel to and spaced apart from said low speed recording zone;

second alphanumeric character generating means positioned adjacent said high speed recording zone for effecting character generation in said high speed recording zone;

motive means for moving recording media through said recording zones;

means for energizing said first character generating means during a low speed recording mode and said second character generating means during a high speed mode of operation;

- means for applying developer material to said recording media; and

means'for rendering said developer applying means operable in the first mode of operation for rendering visible latent images recorded at said low speed recording zone and in a second mode of operation for rendering visible latent images recorded in said high speed recording zone.

4. Apparatus according to claim 3 wherein,

said first alphanumeric character generating means adjacent said low speed recording zone comprises a movable array of conductive styli; and

said means for energizing said second character generator comprises control means for selectively incrementing said movable array through said low speed recording zone in the direction of said elongated dimension.

5. Apparatus according to claim 3 wherein,

said means for applying developer material to said recording medium comprises:

a first developing applicator member having a developing surface positioned adjacent said low speed recording zone;

means for selectively moving said developing surface in developing relationship with said recording medium during the low speed recording mode;

a second developing applicator member having a developing periphery positioned adjacent said high speed recording zone;

means for moving said periphery in developing relationship with said recording medium during a high speed recording mode, said developing surface being moved in contact with said periphery during a low speed recording mode; and

means for applying developing material to said second applicator.

6. Recording apparatus according to claim 5 wherein, said means for moving said periphery in developing relationship with said recording medium comprises drive means for effecting continuous movement of said second developing applicator during said high speed recording mode and intermittent movement during said low speed recording mode.

7. Apparatusfor rendering visible latent electrostatic images on a charge-retentive recording surface, said apparatus comprising: applicator means for presenting electroscopic marking particles to said recording surface, said applicator means including a pair of distinct members: means rendering said applicator means operable during a first mode of operation to effect application of said electroscopic marking particles to said recording surface at a first recording zone: and means for rendering said applicator means operable during a second mode of operation to effect application of said electroscopic marking particles to said recording surface adjacent a second recording zone, the relative movement between said charge-retentive surface and said applicator means being the same regardless of mode of operation.

8. Apparatusaccording to claim 7 wherein,

said applicator means comprises a first rotatable member and means for continuously rotating said member during one of said modes of operation and intermittently rotating said rotatable member in the other of said modes of operation;

9. A dual comprising:

a linear array of conductive styli;

mode electrographic apparatus means for moving a web of insulative recording medium first between said fixed array of styli and said elongated backing electrode and secondly between said elongated backing electrode and said incrementally movable array of styli; and

second development applicator meanw positioned along the path of the web between the first and second recording zones having a surface capable of retaining electroscopic marking particles and rotatable about an axis parallel to the axis of said first developing applicator means. for bringing electroscopic marking particles into contact with only said web in one recording mode and into contact with the surface of said first applicator means and said web in a second recording mode.

10. Apparatus according to claim 9 including,

means for effecting continuous rotation of said second development applicator during said second recording mode and intermittent movement thereof during said first recording mode. 

1. A DUAL MODE ELECTROGRAPHIC RECORDING APPARATUS COMPRISING: a low speed recording zone having an elongated dimension; a movable array of conductive styli positioned at said low speed recording zone; styli control means for selectively incrementing said movable array through said low speed recording zone in the direction of said elongated dimension; a high speed recording zone having an elongated dimension substantially parallel to said elongated dimension of said low speed recording zone; a fixed array of conductive styli positioned in said high speed recording zone substantially parallel to the elongated dimension thereof; motive means for moving a recording medium through said high speed and low speed recording zones in that order; logic means responsive to either a low speed or high speed recording mode for pulsing said movable or fixed arrays, respectively, whereby latent electrostatic charge patterns are placed on said recording medium representative of information to be recorded; first developing applicator means positioned adjacent said low speed recording zone and having a developing surface; means for selectively moving said developing surface into developing relationship with said recording medium at said low speed recording zone during the low speed recording mode; a second developing applicator means having a developing periphery and positioned adjacent said high speed recording zone; means for moving said periphery in developing relationship with said recording medium during said high speed recording mode, said last recited means being adapted for moving said developing surface in developing relationship with said recording medium and in contact with said periphery during said low speed recordinG mode, means for supplying developing material to said second applicator means.
 1. A DUAL MODE ELECTROGRAPHIC RECORDING APPARATUS COMPRISING: a low speed recording zone having an elongated dimension; a movable array of conductive styli positioned at said low speed recording zone; styli control means for selectively incrementing said movable array through said low speed recording zone in the direction of said elongated dimension; a high speed recording zone having an elongated dimension substantially parallel to said elongated dimension of said low speed recording zone; a fixed array of conductive styli positioned in said high speed recording zone substantially parallel to the elongated dimension thereof; motive means for moving a recording medium through said high speed and low speed recording zones in that order; logic means responsive to either a low speed or high speed recording mode for pulsing said movable or fixed arrays, respectively, whereby latent electrostatic charge patterns are placed on said recording medium representative of information to be recorded; first developing applicator means positioned adjacent said low speed recording zone and having a developing surface; means for selectively moving said developing surface into developing relationship with said recording medium at said low speed recording zone during the low speed recording mode; a second developing applicator means having a developing periphery and positioned adjacent said high speed recording zone; means for moving said periphery in developing relationship with said recording medium during said high speed recording mode, said last recited means being adapted for moving said developing surface in developing relationship with said recording medium and in contact with said periphery during said low speed recordinG mode, means for supplying developing material to said second applicator means.
 2. Recording apparatus according to claim 1 wherein, said means for moving said periphery in developing relationship with said recording medium comprises drive means for effecting continuous movement of said second developing applicator during said high speed recording mode and intermittent movement during said low speed recording mode.
 3. Dual mode recording apparatus comprising: a low speed recording zone having an elongated dimension; first alphanumeric character generating means positioned adjacent said low speed recording zone; control means for said first alphanumeric character generating means for effecting character generation in said low speed recording zone in the direction of said elongated dimension; a high speed recording zone having an elongated dimension substantially parallel to and spaced apart from said low speed recording zone; second alphanumeric character generating means positioned adjacent said high speed recording zone for effecting character generation in said high speed recording zone; motive means for moving recording media through said recording zones; means for energizing said first character generating means during a low speed recording mode and said second character generating means during a high speed mode of operation; means for applying developer material to said recording media; and means for rendering said developer applying means operable in the first mode of operation for rendering visible latent images recorded at said low speed recording zone and in a second mode of operation for rendering visible latent images recorded in said high speed recording zone.
 4. Apparatus according to claim 3 wherein, said first alphanumeric character generating means adjacent said low speed recording zone comprises a movable array of conductive styli; and said means for energizing said second character generator comprises control means for selectively incrementing said movable array through said low speed recording zone in the direction of said elongated dimension.
 5. Apparatus according to claim 3 wherein, said means for applying developer material to said recording medium comprises: a first developing applicator member having a developing surface positioned adjacent said low speed recording zone; means for selectively moving said developing surface in developing relationship with said recording medium during the low speed recording mode; a second developing applicator member having a developing periphery positioned adjacent said high speed recording zone; means for moving said periphery in developing relationship with said recording medium during a high speed recording mode, said developing surface being moved in contact with said periphery during a low speed recording mode; and means for applying developing material to said second applicator.
 6. Recording apparatus according to claim 5 wherein, said means for moving said periphery in developing relationship with said recording medium comprises drive means for effecting continuous movement of said second developing applicator during said high speed recording mode and intermittent movement during said low speed recording mode.
 7. Apparatus for rendering visible latent electrostatic images on a charge-retentive recording surface, said apparatus comprising: APPLICATOR MEANS FOR PRESENTING ELECTROSCOPIC MARKING PARTICLES TO SAID RECORDING SURFACE, SAID APPLICATOR MEANS INCLUDING A PAIR OF DISTINCT MEMBERS: MEANS RENDERING SAID APPLICATOR MEANS OPERABLE DURING A FIRST MODE OF OPERATION TO EFFECT APPLICATION OF SAID ELECTROSCOPIC MARKING PARTICLES TO SAID RECORDING SURFACE AT A FIRST RECORDING ZONE: AND MEANS FOR RENDERING SAID APPLICATOR MEANS OPERABLE DURING A SECOND MODE OF OPERATION TO EFFECT APPLICATION OF SAID ELECTROSCOPIC MARKING PARTICLES TO SAID RECORDING SURFACE ADJACENT A SECOND RECORDING ZONE, THE RELATIVE MOVEMENT BETWEEN SAID CHARGE-retentive surface and said applicator means being the same regardless of mode of operation.
 7. Apparatus for rendering visible latent electrostatic images on a charge-retentive recording surface, said apparatus comprising: applicator means for presenting electroscopic marking particules to said recording surface, said applicator means including a pair of distinct members; means rendering said applicator means operable during a first mode of operation to effect application of said electroscopic marking particules to said recording surfaces ata first recording zone; and means for rendering said applicator means operable during a second mode of operation to effect application of said electroscopic marking particles to said recording surfaces adjacent a second recording zone, the relative movement between said charge-retentive surface and said applicator means being the same regardless of mode of operation.
 8. Apparatus according to claim 7 wherein, said applicator means comprises a first rotatable member and means for continuously rotating said member during one of said modes of operation and intermittently rotating said rotatable member in the other of said modes of operation; said applicatormeans further comprising a second rotatable member and means for driving said member in developing relationship with said charge-retentive surface during saidother of said modes of operation and operative to discontinue movement thereof in said one mode of operation.
 8. Apparatus according to claim 7 wherein, said applicator means comprises a first rotatable member and means for continuously rotating said member during one of said modes of operation and intermittently rotating said rotatable member in the other of said modes of operation; said applicator means further comprising a second rotatable member and means for moving said member in developing relationship with said charge-retentive surface during said other of said modes of operation and operative to discontinue movement thereof in said one mode of operation.
 9. A dual mode electrographic apparatus comprising: a linear array of conductive styli; an elongated backing electrode defining a first recording station; means for selectively inCrementing said linear array of styli through said first recording zone and opposite said backing electrode during a first recording mode; first developer applicator means having an arcuate surface capable of retaining electroscopic marking particles for bringing said particles to said first recording zone, said applicator being selectively rotatable about an axis substantially parallel to said first recording zone; a fixed linear array of conductive styli positioned opposite said backing electrode and substantially coextensive therewith; means for moving a web of insulative recording medium first between said fixed array of styli and said elongated backing electrode and secondly between said elongated backing electrode and said incrementally movable array of styli; and second evelopment applicator means positioned along the path of the web between the first and second recording zones having a surface capable of retaining electroscopic marking particles and rotatable about an axis parallel to the axis of said first developing applicator means for bringing electroscopic marking particles into contact with only said web in one recording mode and into contact with the surface of said first applicator means and said web in a second recordingmode.
 9. A DUAL MODE ELECTROGRAPHIC APPARATUS COMPRISING: a linear array of conductive styli; an elongated backing electrode defining a first recording station; means for selectively incrementing said linear array of styli through said first recording zone and opposite said backing electrode during a first recording mode; first developer applicator means having an arcuate surface capable of retaining electroscopic marking particles for bringing said particles to said first recording zone, said applicator being selectively rotatable about an axis substantially parallel to said first recording zone; a fixed linear array of conductive styli positioned opposite said backing electrode and substantially coextensive therewith; means for moving a web of insulative recording medium first between said fixed array of styli and said elongated backing electrode and secondly between said elongated backing electrode and said incrementally movable array of styli; and second development applicator meanw positioned along the path of the web between the first and second recording zones having a surface capable of retaining electroscopic marking particles and rotatable about an axis parallel to the axis of said first developing applicator means for bringing electroscopic marking particles into contact with only said web in one recording mode and into contact with the surface of said first applicator means and said web in a second recording mode. 